(19)

(11)

EP 1 697 710 A2

(12)

(88) Date of publication A3: 18.08.2005 (43) Date of publication: 06.09.2006 Bulletin 2006/36 (21) Application number: 04798706.0 (22) Date of filing: 29.11.2004

(51) International Patent Classification (IPC):  G01L 1/14(2006.01) (86) International application number: PCT/GB2004/005026 (87) International publication number: WO 2005/055426 (16.06.2005 Gazette 2005/24)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LU MC NL PL PT RO SE SI SK TR (30) Priority: 29.11.2003 US 724336 (71) Applicant: TT Electronics Technology Limited Cambridge CB2 5GG (GB)	(72) Inventor: SILLS, Colin Stuart Harston, Cambridge CB2 5GG (GB) (74) Representative: Beresford, Keith Denis Lewis et al BERESFORD & Co. 16 High Holborn London WC1V 6BX London WC1V 6BX (GB)